Pharmacology & Therapeutics Flashcards
6 cards from real PSI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Pharmacology & Therapeutics flashcards as text
Which drug used in Parkinson's disease is a dopamine precursor?
Answer: Levodopa
Levodopa crosses the blood-brain barrier and is decarboxylated to dopamine in the brain. It is the most effective symptomatic treatment for Parkinson's disease.
Which NSAID is most COX-2 selective and associated with increased cardiovascular risk?
Answer: Celecoxib
Celecoxib selectively inhibits COX-2, reducing GI side effects compared to non-selective NSAIDs, but COX-2 selectivity shifts the prostanoid balance towards thrombosis, increasing CV risk.
Which antiepileptic is contraindicated in pregnancy due to neural tube defect risk?
Answer: Sodium valproate
Sodium valproate is a potent teratogen — it causes neural tube defects, neurodevelopmental disorders and other congenital malformations. It must be used with pregnancy prevention programme (PREVENT) in women of childbearing age.
Digoxin toxicity is worsened by hypokalaemia because:
Answer: Potassium competes with digoxin for the same binding site on Na+/K+ ATPase
Potassium and digoxin bind competitively to Na+/K+ ATPase. When potassium is low, more binding sites are available for digoxin, increasing its inhibitory effect and risk of toxicity.
Which drug class inhibits neuraminidase and is used to treat influenza?
Answer: Oseltamivir (Tamiflu)
Oseltamivir inhibits viral neuraminidase, preventing release of new viral particles from infected cells and limiting spread of influenza A and B.
Lithium toxicity risk increases with concurrent use of which drug?
Answer: NSAIDs (reduce renal lithium excretion)
NSAIDs inhibit prostaglandin-mediated renal blood flow, reducing GFR and lithium excretion. This can rapidly elevate lithium plasma levels into the toxic range.